JP2013230892A - Sheet stacking apparatus and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet stacking apparatus that can prevent occurrence of stacking deviation of two or more sheets stacked into a stacking tray, and to provide an image forming apparatus with the same.SOLUTION: A finisher includes: a bundle discharge roller pair 130; a sheet stacking means which has a lower stacking tray 137, an abutment member 170 on which a sheet is abuttable, and a sheet stacking height detecting sensor for detecting a height of the sheets on the abutment member side, the sheet stacking means configured to stack the sheet while lowering the lower stacking tray in accordance with a detection result; tray paddles 301 coming into contact with the sheet discharged from the bundle discharge roller pair 130 in a direction from a top of the sheet, to bring the sheet into abutment on the abutment member 170; a stacking amount detection means for detecting a stacking amount of the sheet stacked on the lower stacking tray 137; and a finisher control unit for performing control of reducing a relative distance between the tray paddles 301 and the sheet stacked on the lower stacking tray 137 when transporting of the sheet along with increase in the stacking amount of the sheet detected by the stacking amount detection means.

Description

  The present invention relates to a sheet stacking apparatus and an image forming apparatus, and more particularly to a sheet stacking apparatus capable of aligning sheets stacked on a stacking tray and an image forming apparatus including the same.

  Conventionally, sheets discharged to a stacking tray on which sheets are stacked can be aligned in the sheet discharge direction (hereinafter simply referred to as “discharge direction”) and the sheet width direction orthogonal to the discharge direction (hereinafter simply referred to as “width direction”). A sheet stacking apparatus is known (see Patent Document 1).

  For example, in the sheet stacking apparatus described in Patent Document 1, when a sheet is discharged to a stacking tray having a stacking surface inclined by the sheet discharge unit, the sheet is transferred to the upstream side by a transfer unit, and the upstream end of the sheet is moved. The sheet is aligned in the discharge direction by abutting against the abutting member. Further, the sheet is aligned in the width direction by moving the pair of alignment members in the width direction and causing the pair of alignment members to abut against both ends of the sheet in the width direction. This is performed every time the sheets are discharged, and the sheets are stacked while the stacking tray is lowered so that the height (paper surface height) of the sheets stacked on the stacking tray does not exceed a predetermined height.

JP 2002-211829 A

  In the above-described sheet stacking apparatus, since the angle α formed between the stacking surface of the stacking tray 1137 and the abutting surface of the abutting member is an acute angle, when the upstream end of the sheet abuts against the abutting surface, the upstream end is forced downward. In some cases, the curve is curved to have a convex shape indicated by a dotted line Sb in FIG. When the discharged sheets are stacked in such a shape, an air layer is formed between the sheets on the abutting member side, and as shown in FIG. The paper surface height Ha on the abutting member side relative to the paper surface height Hb is relatively high. Therefore, the inclination of the sheet downstream from the central portion in the discharge direction becomes closer to the horizontal as the number of stacked sheets increases.

  On the other hand, the transfer unit 1301 of the above-described sheet stacking apparatus moves from the abutting member side to a predetermined transfer position on the stacking surface of the stacking tray 1137 so as to transfer the sheet on the stacking tray to the abutting member side. It is configured. Further, the sheet surface height of the sheet is controlled to be lowered based on the height Ha on the abutting member side so as not to affect the sheet discharge from the sheet discharge unit. Therefore, if the height Ha on the abutting member side with respect to the height Hb of the central portion in the discharge direction is relatively increased due to an increase in the loading amount, the sheet surface height of the sheet at the transfer position by the transfer unit is reduced. There is a risk that the contact pressure between the transfer means and the sheet may decrease. As a result, the transfer unit cannot transfer the sheets, and there is a possibility of causing a stacking error.

  Further, the discharged sheet has a reaction force when the downstream end is landed on the inclined stacking surface of the stacking tray 1137, and a sliding resistance force between the top surface of the sheets stacked on the stacking tray 1137 after landing, In response, these forces act as braking forces and stop after a predetermined distance. However, when the sheet stacking amount increases, the inclination of the upper surface of the sheets stacked on the stacking tray 1137, which is the landing point at the downstream end of the discharged sheets, becomes nearly horizontal, so the reaction force and sliding at the time of landing The resistance is reduced and the running distance (flying distance) is increased. When the sheet stacking amount increases in this way, the sheet is stacked farther and on the upper surface of the stacking sheet having a small inclination, so that the return along the inclined surface due to the weight of the sheet becomes insufficient, and a stacking deviation may occur. was there.

  SUMMARY An advantage of some aspects of the invention is that it provides a sheet stacking apparatus capable of preventing the occurrence of misalignment of a plurality of sheets stacked on a stacking tray, and an image forming apparatus including the sheet stacking apparatus.

  The present invention relates to a sheet stacking apparatus, a sheet discharge unit for discharging sheets, a stacking tray for stacking sheets discharged from the sheet discharge unit, and sheets stacked on the stacking tray below the sheet discharge unit. An abutting member formed so as to be able to abut an end portion thereof, and a sheet height detection sensor that detects a height of the sheet loaded on the stacking tray on the abutting member side, and the sheet height detection According to the detection result of the sensor, the sheet stacking means for stacking sheets while lowering the stacking tray, and the sheet discharged from the sheet discharge unit from above are transported toward the butting member and pushed. Transfer means for applying, stacking amount detection means for detecting the stacking amount of sheets stacked on the stacking tray, and increase in the stacking amount of sheets detected by the stacking amount detection unit When, characterized by comprising a control unit for controlling to approach the said top surface of the transfer means and the uppermost sheet stacked on the stacking tray at the time of transfer.

  According to the present invention, when the amount of sheets stacked on the stacking tray increases, the relative distance between the uppermost sheet on the stacking tray and the transfer unit is reduced, thereby stacking a plurality of sheets stacked on the stacking tray. The occurrence of deviation can be prevented.

It is sectional drawing which shows typically the whole structure of the composite apparatus which concerns on embodiment of this invention. It is sectional drawing which shows the finisher which concerns on this embodiment typically. It is a block diagram of the control part which controls the compound apparatus concerning this embodiment. It is a block diagram of the finisher control part which controls the finisher concerning this embodiment. It is a perspective view which shows the width direction alignment part provided in the finisher which concerns on this embodiment. It is a perspective view which shows the discharge direction alignment part provided in the finisher which concerns on this embodiment. It is a figure which shows the stand-by position and transfer position of the tray paddle of the discharge direction alignment part which concern on this embodiment. It is a perspective view which shows the lower stacking tray provided in the finisher which concerns on this embodiment. It is a perspective view which shows the lower tray area detection sensor which detects the position of the height direction of the lower stacking tray which concerns on this embodiment. It is a figure which shows the sheet height detection sensor which detects the height of the sheet | seat loaded on the lower stacking tray which concerns on this embodiment. It is a figure which shows the state which a front alignment member, a back alignment member, a paddle holder, and a lower stacking tray are located in a home position. It is a figure which shows the state which moved the front alignment member, the back alignment member, and the paddle holder to the sheet | seat reception position. It is a figure which shows the state in which a tray paddle aligns a sheet | seat in a discharge direction in the 1st transfer position. It is a figure which shows the state which a front alignment member and a back alignment member align a sheet | seat in the width direction. FIG. 10 is a diagram illustrating a state in which the front alignment member and the back alignment member are further lowered according to the height of the lower stacking tray to align the sheets in the width direction. It is a figure which shows the state which the sheet | seat loaded on the lower stacking tray increased, and the lower stacking tray fell to the 2nd height. It is a figure showing the state where a tray paddle descends from the 1st transfer position to the 2nd transfer position. 6 is a flowchart showing a sheet stacking operation on a lower stacking tray by a finisher according to the present embodiment. It is sectional drawing which shows typically the stacking tray of the sheet | seat stacking apparatus which concerns on a prior art example.

  Hereinafter, an image forming apparatus including a sheet stacking apparatus according to an embodiment of the present invention will be described with reference to the drawings. The image forming apparatus according to the present embodiment is an image forming apparatus provided with a sheet stacking apparatus capable of aligning sheets stacked on a stacking tray, such as a copying machine, a printer, a facsimile, and a composite device thereof. The following embodiments will be described using a monochrome / color composite device (hereinafter referred to as “composite device”) 1 as an image forming apparatus.

  Hereinafter, a composite device 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 18. First, the overall configuration of the composite device 1 will be described along the movement of the seat with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view schematically showing the overall structure of a composite device 1 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing the finisher 100 according to the present embodiment.

  As shown in FIG. 1, the composite apparatus 1 according to the present embodiment includes a copying machine 600 that forms an image on a sheet, and a finisher 100 as a sheet stacking apparatus. The finisher 100 according to the present embodiment is configured to be detachable from the copying machine 600 and can be used as an option for the copying machine 600 that can be used alone.

  In the present embodiment, the detachable finisher 100 described above will be used. However, in the present invention, the finisher 100 and the copying machine 600 may be an integrated composite device. In the following, the position where the user faces the operation unit 601 for performing various inputs / settings on the composite device 1 is referred to as “front” of the composite device 1, and the back side of the composite device is referred to as “back”. That is, FIG. 1 shows the internal configuration of the composite device 1 as seen from the front side, and the finisher 100 is connected to the side of the copier 600.

  The copying machine 600 includes an operation unit 601, a document feeding device 602 that can feed a document, an image reader 603 that reads information on a document fed from the document feeding device 602, and an image that forms an image on a sheet. Forming portion 604. Further, the copier 600 includes a sheet storage unit 605 that stores sheets, and a sheet feeding unit 606 that feeds sheets stored in the sheet storage unit 605 to the image forming unit 604.

  When a document is set on the document feeder 602 of the copying machine 600, the document is fed one by one from the first page in order, and the image information of the document is read by the image reader 603. When the image information is read, toner images of colors of yellow, magenta, cyan, and black are formed on the photosensitive drums 914a to 914d of the image forming unit 604 based on the read image information. In parallel with the toner image forming operation, the sheet feeding unit 606 selectively feeds the sheets from the feeding cassettes 909 a and 909 b of the sheet storage unit 605. Then, at a predetermined timing, the sheet is sent to the transfer positions of the photosensitive drums 914a to 914d, and the toner images of the respective colors formed on the photosensitive drums 914a to 914d are sequentially superimposed and transferred onto the sheet. Thereafter, the unfixed toner image formed on the sheet is fixed by the fixing device 904, and the sheet is sent to the finisher 100 by the discharge roller pair 907.

  In the case of duplex printing, after the sheet is reversed by the reversing roller 905, the reversed sheet is conveyed by the conveying rollers 906a to 906f provided in the reversing conveyance path to the image forming unit 604, and the above is repeated.

  The finisher 100 is connected to the downstream side of the copier 600, and can introduce a sheet sent from the copier 600 and perform saddle processing online. As shown in FIG. 2, the finisher 100 includes a finisher main body 400 and an inserter 900 that can insert a sheet into a conveyance path 109 inside the finisher main body 400. The inserter 900 is provided in the upper part of the finisher main body 400. For example, the inserter 900 is used to insert an insert sheet between the first page, the last page of a sheet bundle, or a sheet on which an image is formed by the copying machine 600. is there.

  The sheet fed from the copying machine 600 is first delivered to the entrance roller pair 102 of the finisher 100. At this time, the sheet delivery timing is simultaneously detected by the entrance sensor 101. While the sheet delivered to the entrance roller pair 102 passes through the conveyance path, the lateral registration detection sensor 104 detects a lateral registration error in the sheet width direction (hereinafter simply referred to as “width direction”) with respect to the center position. When the horizontal registration detection sensor 104 detects a horizontal registration error, the shift unit 108 performs a horizontal registration detection process.

  When the lateral registration detection process by the shift unit 108 is completed, the sheet is conveyed by the conveyance roller pair 110 and further conveyed downstream by the buffer roller pair 115. Here, when the sheet is discharged to the upper stacking tray 136, the upper path switching member 118 is moved to the position of the broken line shown in FIG. 2 by driving means such as a solenoid (not shown), and the sheet passes through the upper path conveying path 117. Then, the sheet is discharged to the upper stacking tray 136 by the upper discharge roller pair 120. On the other hand, when the sheet is discharged to the lower stacking tray 137, the upper path switching member 118 is moved to the position of the solid line shown in FIG.

  Here, when the sheet conveyed to the bundle conveyance path 121 is subjected to saddle stitching (saddle processing), the saddle path switching member 125 is moved to the position of the broken line shown in FIG. 2 by driving means such as a solenoid (not shown). As a result, the sheet is guided to the saddle path 133 and is conveyed to the saddle unit 135 by the saddle entrance roller pair 134 to perform saddle stitching processing. The description of the saddle stitching process is omitted here. On the other hand, when the saddle stitching process is not performed, the saddle path switching member 125 is moved to the position of the solid line shown in FIG. 2, and the sheets are sequentially conveyed onto the processing tray 138 of the staple unit 127. The sheets conveyed onto the processing tray 138 are aligned in the sheet discharge direction (hereinafter simply referred to as “discharge direction”) and the width direction, and then are bound by the stapler 132. The sheet processing in the stapling unit 127 will not be described here.

  The sheets that have undergone predetermined sheet processing by the staple unit 127 are discharged to a lower stacking tray 137 as a stacking tray by a bundle discharge roller pair 130 serving as a sheet discharging unit. When the predetermined sheet processing is not performed in the staple unit 127, the sheet is transferred from the lower discharge roller pair 128 to the bundle discharge roller pair 130 and discharged to the lower stacking tray 137. Thereafter, the sheets discharged to the lower stacking tray 137 are aligned in the width direction and the discharge direction on the lower stacking tray 137 by the width direction aligning unit 200 and the discharge direction aligning unit 300. The width direction alignment by the width direction alignment unit 200 and the discharge direction alignment process by the discharge direction alignment unit 300 will be described in detail later. Further, the lower stacking tray 137 has a sheet height (paper surface height) detected by a sheet height detection sensor 510 described later, and the sheet height detection sensor 510 has a predetermined height. The sheets are stacked while descending according to the detection result. The lower stacking tray 137, the sheet height detection sensor 510, and the butting member 170 constitute a sheet stacking unit, and the lower stacking tray 137 will be described in detail later.

  Next, the control unit 6 that controls the composite device 1 according to the present embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 is a block diagram of the control unit 6 that controls the composite device 1 according to the present embodiment. FIG. 4 is a block diagram of the finisher control unit 618 that controls the finisher 100 according to the present embodiment.

  As shown in FIG. 3, the control unit 6 includes a CPU circuit unit 610, a document feeding device control unit 614, an image reader control unit 615, an image signal control unit 616, a printer control unit 617, and a finisher control unit. 618. In the present embodiment, the CPU circuit unit 610, the document feeder control unit 614, the image reader control unit 615, the image signal control unit 616, and the printer control unit 617 are mounted on the copier 600, and the finisher control unit 618 is It is mounted on the finisher 100.

  The CPU circuit unit 610 includes a CPU 611, a ROM 612, and a RAM 613. In accordance with the program stored in the ROM 612 and the instruction information input from the operation unit 601, the CPU 611 controls the document feeder control unit 614, the image reader control unit 615, the image signal control unit 616, the printer control unit 617, and the finisher control unit. 618 etc. are controlled. The RAM 613 is used as an area for temporarily storing control data and a work area for operations associated with control.

  The document feeder control unit 614 controls the document feeder 602, and the image reader controller 615 controls the image reader 603 that reads information on the document fed from the document feeder 602 (see FIG. 1). ). Note that the document data read by the image reader controller 615 is output to the image signal controller 616. A printer control unit 617 controls the copying machine 600. The external interface 619 is an interface for connecting the external computer 620 and the copying machine 600. For example, the print data input from the computer 620 is developed into an image and output to the image signal control unit 616. The image data output to the image signal control unit 616 is output to the printer control unit 617, and an image is formed by the image forming unit 604.

  As shown in FIG. 4, the finisher control unit 618 includes a CPU (microcomputer) 701, a RAM 702, a ROM 703, input / output units (I / O) 705a to 705e, a communication interface 706, and a network interface 704. I have. The finisher control unit 618 includes a transport control unit 707, an intermediate processing tray control unit 708, a binding control unit 709, a stacking tray alignment control unit 710, and a stacking tray control unit 711. The finisher control unit 618 controls various drive motors and sensors shown in FIG. 4 by exchanging information with the CPU circuit unit 610 to perform overall drive control of the finisher 100. For example, the finisher control unit 618 causes the stacking tray alignment control unit 710 capable of executing proximity control described later to execute proximity control.

  Next, the width direction alignment unit 200 that performs alignment processing in the width direction of the sheets discharged to the lower stacking tray 137 will be described with reference to FIG. 5 in addition to FIG. FIG. 5 is a perspective view showing the width direction aligning portion 200 provided in the finisher 100 according to the present embodiment. In the following, the width direction is referred to as the front and back direction.

  As shown in FIG. 2, the width direction alignment unit 200 is provided above the lower stacking tray 137. Further, as shown in FIG. 5, the width direction alignment unit 200 includes a front alignment unit 201b disposed on the front side, a rear alignment unit 201a disposed on the rear side, an upper stay 202, and an alignment member lifting motor M11. And an alignment member elevating HP sensor S11. The front alignment unit 201b and the back alignment unit 201a are attached to the upper stay 202 so as to be symmetrical in the front-rear direction, and the upper stay 202 is supported by the finisher body 400.

  The front alignment unit 201b includes an arm-shaped front alignment member 203b, a pulley support plate 204b, a front alignment member slide motor M9, and a front alignment member HP sensor S9. The back alignment unit 201a includes an arm-shaped back alignment member 203a, a pulley support plate 204a, a back alignment member slide motor M10, and a back alignment member HP sensor S10. Since the front alignment unit 201b and the back alignment unit 201a have the same basic configuration, the configuration of the back alignment unit 201a will be described here, and the front alignment unit 201b is denoted by the same reference numeral. Description is omitted.

  The rear end of the rear alignment member 203a is supported by the slide member 206, and the slide member 206 is supported by the first alignment support shaft 205 so as to be rotatable and slidable. Further, the slide member 206 holds the second slide drive transmission belt 209 with the slide position detection member 208, and the second slide drive transmission belt 209 is stretched over a pair of slide drive transmission pulleys 210a and 210b. Yes. The slide drive transmission pulleys 210a and 210b are supported by a pulley support shaft 211 that is caulked and coupled to a pulley support plate 204a. The slide drive transmission pulley 210a is connected to a rear alignment member slide motor via a first slide drive transmission belt 212. It is connected to M10.

  The back alignment member 203a is moved in the front-rear direction by the slide member 206 being slid along the first alignment support shaft 205 by the drive of the back alignment member slide motor M10, and the leading end is moved to the end in the width direction of the sheet. The sheets are brought into contact with each other to align the sheets in the width direction. At this time, the home position in the front and back direction of the back alignment member 203a is detected by the back alignment member HP sensor S10 attached to the upper stay 202 via the alignment position detection support plate 214. Then, based on the detected home position and the like, movement control in the front-rear direction is performed by the stacking tray alignment control unit 710 of the finisher control unit 618. The home position in the near back direction of the back aligning member 203a is a position in the near back direction where the sheet can be discharged onto the lower stacking tray 137.

  The first alignment support shaft 205 is supported by alignment member elevating pulleys 215a and 215b, and the alignment member elevating pulley 215a is connected to the second elevating pulley 217 via a drive transmission belt 216. The second elevating pulley 217 is attached to the elevating transmission shaft 218 with a D-cut, and the third elevating pulley 219 is connected to the elevating transmission shaft 218. The third lifting pulley 219 is connected to the alignment member lifting motor M11 via the drive transmission belt 220.

  The back aligning member 203a moves up and down as the first aligning support shaft 205 rotates via the elevating transmission shaft 218 by driving the alignment member elevating motor M11. At this time, the rotation amount of the back alignment member 203a is restricted by the second alignment support shaft 207. Further, the flag portion 215f provided on the alignment member elevating pulley 215b turns on and off the alignment member elevating HP sensor S11 that detects the home position in the elevating direction of the inner alignment member 203a, thereby raising and lowering the inner alignment member 203a. The home position in the direction is detected. Based on the detected home position or the like at the lift position, movement control of the lift position is performed by the stacking tray alignment controller 710 of the finisher controller 618. Since the back alignment member 203a and the front alignment member 203b are connected via the lifting transmission shaft 218, the front alignment member 203b is used to control the lift position of the back alignment member 203a by the stacking tray alignment control unit 710. Synchronize. The home position at the lift position is a position in the lift direction at which the sheet can be discharged onto the lower stacking tray 137.

  Next, a discharge direction alignment unit 300 that performs alignment processing in the discharge direction of the sheets discharged to the lower stacking tray 137 will be described with reference to FIGS. 6 and 7 in addition to FIG. FIG. 6 is a perspective view showing the discharge direction alignment unit 300 provided in the finisher 100 according to the present embodiment. FIG. 7 is a diagram illustrating the standby position and the transfer position of the tray paddle 301 of the discharge direction alignment unit 300 according to the present embodiment.

  As shown in FIG. 2, the discharge direction alignment unit 300 is provided above the lower stacking tray 137. Specifically, the discharge direction alignment unit 300 is supported by a substantially central portion of an upper opening / closing guide 149 provided so as to be positioned above the bundle discharge roller pair 130. The discharge direction aligning unit 300 lowers a tray paddle 301 (to be described later) while rotating it from above the bundle discharge roller pair 130, thereby dropping a sheet discharged from the bundle discharge roller pair 130 onto the lower stacking tray 137. It is made to abut against 170. The abutting member 170 is provided below the bundle discharge roller pair 130 on the upstream side in the sheet discharge direction (hereinafter simply referred to as “upstream side”) in which the sheets are discharged to the lower stacking tray 137 (see FIG. 11). ).

  As shown in FIG. 6, the discharge direction aligning unit 300 includes a tray paddle 301 and a paddle holder 302, and the tray paddle 301 and the paddle holder 302 serve as a transport unit that causes the sheet to abut against the abutting member 170. It is composed.

  The tray paddle 301 has a plurality of paddles and is rotatably supported at the tip of the paddle holder 302. The rotation shaft 315 of the tray paddle 301 is connected to a tray return pulley 316a, and the tray return pulley 316a is connected to the tray return pulley 316b via a drive transmission belt. The tray return pulley 316b is connected to a holder support shaft 303 rotatably supported by the upper opening / closing guide 149. The holder support shaft 303 is drivingly connected to the bundle discharge roller pair 130 via a gear train 317. . That is, the tray paddle 301 is configured to rotate in synchronization with the bundle discharge roller pair 130 that is rotated by driving the bundle discharge motor M5.

  The base end portion of the paddle holder 302 is supported by the holder support shaft 303 and is engaged with a paddle lifting pulley 305 supported by the holder support shaft 303. A lift link pulley 306 is connected to the paddle lift pulley 305, and the lift link pulley 306 is connected to the lift link pulley 309 via a drive transmission belt 307. The lifting link pulley 309 is connected to the lifting gear 312 via the drive transmission belt 310, and the lifting gear 312 is connected to the tray paddle lifting motor M12. As a result, the driving force of the tray paddle lifting motor M12 is transmitted to the paddle holder 302, and the paddle holder 302 rotates (lifts), so that the tray paddle 301 supported at the tip of the paddle holder 302 can freely move up and down. The tray paddle elevating motor M12 is attached to the elevating motor support plate 313, and the elevating motor support plate 313 is attached to the upper stay 202 (see FIGS. 5A and 5B).

  The home position of the paddle holder 302 is detected by the flag portion 302f of the paddle holder 302 blocking the tray paddle HP sensor S12 attached to the upper opening / closing guide 149. Based on the detected home position and the like, the stacking tray alignment control unit 710 performs movement control of the rotation position. For example, the paddle holder 302 is shown in FIG. 7A where the sheet is received above the bundle discharge roller pair 130 and in FIG. 7B where the sheet on the lower stacking tray 137 abuts against the abutting member 170. Movement control is performed between the first transfer position and the first transfer position. Further, the paddle holder 302 is further moved downward from the first transfer position and controlled to move to the second transfer position shown in FIG. 7C in which the relative distance from the uppermost sheet stacked on the lower stacking tray 137 is reduced. Is done. Further, the paddle holder 302 moves to the home position accommodated in the upper opening / closing guide 149 after the end of the job (see, for example, FIG. 6B). Thus, the paddle holder 302 (tray paddle 301) according to this embodiment is controlled to move to the home position, the receiving position, the first transfer position, and the second transfer position. Note that these movement controls will be described in detail later.

  Next, an elevating mechanism and height direction movement control of the lower stacking tray 137 for stacking discharged sheets will be described with reference to FIGS. First, the raising / lowering mechanism of the lower stacking tray 137 will be described with reference to FIGS. FIG. 8 is a perspective view showing the lower stacking tray 137 provided in the finisher 100 according to the present embodiment. FIG. 9 is a perspective view showing lower tray area detection sensors S15 to S17 that detect the position in the height direction of the lower stacking tray 137 according to the present embodiment.

  As shown in FIGS. 8A and 8B, the lower stacking tray 137 includes an elevating unit 500, and a pair of pinion gears 501a and 501b built in the elevating unit 500 is a pair of racks 509a and 509b. Move up and down. Specifically, as shown in FIG. 8C, the pinion gear 501a is connected to the first elevating gear 502 via the second elevating gear 503 and the third elevating gear 504, and the first elevating gear 502 is provided. Is connected to the lifting pulley 505. The lifting pulley 505 is connected to the lower tray lifting motor M13 via the lifting belt 506. The pinion gear 501b is connected to the third elevating gear 504 via the elevating shaft 507. Thus, the lower stacking tray 137 is driven by the lower tray lifting / lowering motor M13 so that the pinion gear 501a and the pinion gear 501b rotate in synchronization with each other, and moves up and down by moving on the rack 509b. Yes.

  An encoder 520 is attached to the first elevating gear 502, and the lower tray position detection sensor S13 detects the on / off state of the encoder 520, thereby detecting the rotation amount of the lower tray elevating motor M13. . Then, the lowering amount of the lower stacking tray 137 is detected from the rotation amount of the lower tray lifting motor M13, and it is possible to detect how much the lower stacking tray 137 is lowered from the initial position. The initial position is a position where the lower stacking tray 137 is positioned when the job is started, and is hereinafter referred to as a home position. Further, the encoder 520 and the lower tray position detection sensor S13 constitute a stacking tray position detection unit and can also form a stacking amount detection unit.

  Further, as shown in FIG. 9 (a), on the far side (lowering unit 500 side) of the lower stacking tray 137, there is a lower stacking tray position detecting unit that can constitute a stacking amount detecting unit at the upstream end. Tray area detection sensors S15 to S17 are mounted side by side in the discharge direction. The lower tray area detection sensors S15 to S17 are turned on when a plurality of flag portions serving as stacking tray position detection means provided at predetermined positions on the area detection plate 515 shield each of the lower tray area detection sensors S15 to S17. It can be switched off. The lower stacking tray 137 is detected such that its position in the height direction is detected by switching on and off the lower tray area detection sensors S15 to S17 by a plurality of flag portions provided at predetermined positions of the area detection plate 515. It has become.

  For example, when the lower stacking tray 137 is located at the home position, the lower tray area detection sensor S15 is turned on by being shielded by the flag portion 515a shown in FIG. 9B, and the lower tray area detection sensors S16 and S17 are shielded from light. It is not (off). That is, when the lower tray area detection sensor S15 is on and the lower tray area detection sensors S16 and S17 are off, it is determined that the lower stacking tray 137 is located at the home position. Thereafter, when the sheet stacking amount increases and descends to the first height, the lower tray area detection sensor S16 is turned on by being shielded by a flag portion (not shown) provided on the area detection plate 515, and the lower tray area detection sensor S17. Is not shielded (off). That is, when the lower tray area detection sensors S15 and S16 are on and the lower tray area detection sensor S17 is off, it is determined that the lower stacking tray 137 is positioned at the first height. Further, when the sheet stacking amount increases and descends to the second height, the lower tray area detection sensor S17 is also shielded by a flag portion (not shown) provided on the area detection plate 515 and turned on. That is, when the lower tray area detection sensors S15, S16, and S17 are on, it is determined that the lower stacking tray 137 is positioned at the second height.

  Thus, the finisher 100 according to this embodiment is provided with two types of sensors that detect the height of the lower stacking tray 137. For example, by detecting with the encoder 520, the amount of movement of the lower stacking tray 137 can be detected in detail. In addition, even when there is a possibility that the actual movement amount and the detection amount may deviate if the elevation is repeated due to backlash or the like of the drive unit, the lower stack tray 137 is detected by the detection by the lower tray area detection sensors S15 to S17. It is possible to detect that the vehicle has been lowered to a predetermined position.

  In this embodiment, the lower tray area detection sensors S15 to S17 are used to detect the first height and the second height of the lower stacking tray 137, but a plurality of lower tray area detection sensors are used. Thus, a plurality of heights may be detected in stages.

  Next, the control operation in the height direction of the lower stacking tray 137 will be described with reference to FIG. FIG. 10 is a diagram illustrating a sheet height detection sensor 510 that detects the height of the sheets stacked on the lower stacking tray 137 according to the present embodiment.

  The movement control in the height direction of the lower stacking tray 137 is performed by detecting the stacking surface 137a of the lower stacking tray 137 and the position in the height direction of the sheets stacked on the stacking surface 137a by the sheet height detection sensor 510. . The sheet height detection sensor 510 is provided below the bundle discharge roller pair 130 and on the upstream side (abutting member side) of the lower stacking tray 137 so as not to affect the sheet discharge. Position detection in the height direction.

  As shown in FIG. 10, the sheet height detection sensor 510 includes a first light receiving sensor 510a, a second light receiving sensor 510b, a third light receiving sensor 510c, and a light emitting sensor 510d. The sheet height detection sensor 510 detects on / off of each sensor by blocking the light from the light emitting sensor 510d received by the first to third light receiving sensors 510a to 510c by a stacked sheet or the like. To do. The lower stacking tray 137 is raised and lowered according to the detection result of the sheet height detection sensor 510.

  For example, at the start of a job in which no sheets are stacked on the lower stacking tray 137 (for example, when positioned at the home position), only the third light receiving sensor 510c is shielded from light by the lower stacking tray 137 and is in an on state. . That is, when only the third light receiving sensor 510c is on, it is determined that there is no sheet in the lower stacking tray 137 or the stacking height is low, and the lower stacking tray 137 is not lowered. Thereafter, the sheets are sequentially stacked, and the second light receiving sensor 510b is shielded from light by the stacked sheets. When the second light receiving sensor 510b is turned on, the lower tray lifting motor M13 is driven to drive the second light receiving sensor 510b. Is lowered until is turned off (light receiving state). In this way, each time the second light receiving sensor 510b is turned on, the lower tray elevating motor M13 is driven, and the lower stacking tray 137 is repeatedly lowered to stack the sheets while lowering the lower stacking tray 137. Go. The lower stacking tray 137 is provided with a lower tray sheet presence / absence detection sensor S21 and a sheet presence / absence detection flag 516, and the presence / absence of a sheet is detected by turning on / off the lower tray sheet presence / absence detection sensor S21.

  Next, the sheet stacking operation on the lower stacking tray by the finisher 100 according to the present embodiment will be described with reference to FIGS. 11 to 17 along the flowchart shown in FIG. FIG. 11 is a diagram illustrating a state in which the front alignment member 203b, the back alignment member 203a, the paddle holder 302, and the lower stacking tray 137 are located at the home position. FIG. 12 is a diagram illustrating a state in which the front alignment member 203b, the back alignment member 203a, and the paddle holder 302 are moved to the sheet receiving position. FIG. 13 is a diagram illustrating a state in which the tray paddle 301 aligns sheets in the discharge direction at the first transfer position. FIG. 14 is a diagram illustrating a state in which the front alignment member 203b and the back alignment member 203a align the sheets in the width direction. FIG. 15 is a diagram illustrating a state in which the front alignment member 203b and the back alignment member 203a are further lowered according to the height of the lower stacking tray 137 to align the sheets in the width direction. FIG. 16 is a diagram illustrating a state where the number of sheets stacked on the lower stacking tray 137 is increased and the lower stacking tray 137 is lowered to the second height. FIG. 17 is a diagram illustrating a state in which the tray paddle 301 is lowered from the first transfer position to the second transfer position. FIG. 18 is a flowchart showing a sheet stacking operation on the lower stacking tray 137 by the finisher 100 according to this embodiment.

  When the user sets the unbound bottom discharge stacking mode and starts the unbound bottom stacking mode, the front alignment member 203b and the back alignment member 203a are initially operated to move to the home position (step S801). Similarly, the paddle holder 302 is initially moved to the home position, and the lower stacking tray 137 is initially moved to the home position (steps S802 and S803). When the front alignment member 203b, the back alignment member 203a, the paddle holder 302, and the lower stacking tray 137 are initially operated and moved to the home position or the initial position, the state shown in FIG. 11 is obtained.

  Next, after the initial operation is completed, the front alignment member 203b, the back alignment member 203a, and the tray paddle 301 are moved to the receiving position shown in FIG. First, according to the sheet size information input by the operation unit 601, the front alignment member 203b and the back alignment member 203a are slid by a predetermined amount in the front-rear direction and then rotated by a predetermined amount. Similarly, the paddle holder 302 is rotated by a predetermined amount. The receiving position is a position where the distance between the front alignment member 203b and the back alignment member 203a is set to be a predetermined amount larger than the length in the width direction of the sheet and does not interfere with the discharged sheet. Further, the tray paddle 301 is not in contact with the sheet being discharged. Since the lower stacking tray 137 has the home position as the receiving position, preparation for receiving sheets is completed.

  Next, a sheet on which an image has been formed by the above-described image forming operation is fed from the discharge roller pair 907 of the copying machine 600 to the finisher 100 and discharged from the bundle discharge roller pair 130 to the lower stacking tray 137 (step S804). When the trailing edge of the sheet passes through the nip of the bundle discharge roller pair 130, the tray paddle 301 is lowered from the sheet receiving position to the first transport position. When the tray paddle 301 is lowered, the tray paddle 301 comes into contact with the sheet discharged from the bundle discharge roller pair 130 and drops the sheet onto the lower stacking tray 137. At this time, since the tray paddle 301 rotates in synchronization with the bundle discharge roller pair 130, the sheet S is abutted against the abutting member 170 while being dropped on the lower stacking tray 137, as shown in FIG. It is aligned with the discharge direction (step S805). The timing for rotating the paddle holder 302 starts after a predetermined time after the trailing edge of the sheet S passes through the nip, and the tray paddle 301 is moved at the first transfer position (the position shown in FIG. 13) for a predetermined time. After rotating, it rises to the receiving position (position shown in FIG. 12).

  Next, as shown in FIG. 14, the front alignment member 203b and the back alignment member 203a waiting at a position larger than the length in the width direction of the sheet S by a predetermined amount (A shown in FIG. 14B) are set to the sheet width. And the sheet S is sandwiched and aligned in the width direction. When the sheet S is nipped and aligned in the width direction, the state shown in FIG. 14C is obtained, and the sheet S is aligned in the width direction at a predetermined position on the lower stacking tray 137 (step S806). When the alignment in the width direction of the sheet S is completed, the front alignment member 203b and the back alignment member 203a are moved to the receiving position shown in FIG.

  Next, the state of the second light receiving sensor 510b is confirmed. If the second light receiving sensor 510b is on, the lower stacking tray 137 is lowered until the second light receiving sensor 510b is turned off (steps S807 and S808). On the other hand, if the second light receiving sensor 510b is off, the next sheet is received and this is performed every time the sheet is discharged. In this manner, discharge of sheets, alignment in the discharge direction, alignment in the width direction, and lowering of the lower stacking tray 137 are repeated, and the sheets are sequentially stacked on the lower stacking tray 137.

  By continuing the above-described control, when the lower stacking tray 137 moves to a position that is lowered by a certain amount from the home position, the lower tray position detection sensor S13 detects that the lower loading tray 137 has been lowered by a certain amount (step S809). . Then, the alignment member elevating motor M11 is driven, and the front alignment member 203b and the back alignment member 203a are lowered from the position shown in FIG. 15A to the position shown in FIG. 15B, and the sheets can be aligned in the width direction. It moves to the correct position (step S810). The front alignment member 203b and the back alignment member 203a are configured to be lowered to a position where the sheets can be aligned in the width direction as the amount of sheets stacked on the lower stack tray 137 exceeds a predetermined amount. Yes. Thereby, for example, even when the downstream side of the sheet is in a lying state (see FIG. 16), the front alignment member 203b and the back alignment member 203a can be aligned in the width direction. Here, the state in which the sheets fall asleep means a state in which the inclination of the uppermost sheet stacked on the lower stacking tray 137 approaches the horizontal and becomes smaller.

  When the amount of sheets S stacked on the lower stacking tray 137 increases and the lower stacking tray 137 descends to the first height, the lower tray area detection sensor S16 is turned on (step S811). When the lower tray area detection sensor S16 is turned on, the rotation amount of the paddle holder 302 is set to the second transfer position where the relative distance between the tray paddle 301 and the sheets stacked on the lower stacking tray 137 is reduced (step S812). That is, the tray paddle 301 is set to transfer the sheet at the second transfer position after the sheet stacking amount exceeds a predetermined stacking amount. Note that switching between the first transfer position and the second transfer position is performed while the sheet is being discharged, and image formation or the like is not waited during that time. If the sheet is not the final sheet, the process proceeds to step S804 and the above is repeated. If the sheet is the final sheet, the job is terminated (step S813).

  As described above, the finisher 100 according to the present embodiment moves the tray paddle 301 to the second position below the first transfer position when the stack amount of sheets stacked on the lower stack tray 137 exceeds a predetermined stack amount. The sheet is transferred toward the abutting member 170 at the transfer position. For this reason, when the sheet stacking amount increases, the inclination of the sheet upper surface (uppermost sheet) becomes smaller, and even when the sheet surface height at the first transfer position becomes lower, the tray paddle 301 and the sheet It is possible to prevent the contact pressure from becoming small. Accordingly, it is possible to prevent occurrence of sheet stacking deviation that occurs because the sheets cannot be transferred. Further, since the transfer is performed at the second transfer position located below the first transfer position, the transfer force can be increased.

  Further, in the finisher 100 according to the present embodiment, when the trailing edge of the sheet passes through the nip of the bundle discharge roller pair 130, the paddle holder 302 is rotated to lower the tray paddle 301. For this reason, an increase in the amount of stacked sheets reduces the inclination of the upper surface of the sheet, and the tray paddle 301 transports while dropping the sheet even when the amount of jump when the sheet is discharged from the bundle discharge roller pair 130 can increase. It is possible to prevent the sheet from being unable to move.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above. In addition, the effects described in the embodiments of the present invention only list the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments of the present invention.

  For example, in the present embodiment, when the stacking amount of sheets exceeds a predetermined stacking amount, the paddle holder 302 is moved down so as to be close to the sheets stacked on the tray paddle 301 and the lower stacking tray 137. However, the present invention is not limited to this. For example, it may be a control that adjusts the lowering amount of the lower stacking tray 137 or raises the lower stacking tray by a predetermined amount based on the relative distance between the tray paddle 301 and the sheets stacked on the lower stacking tray 137. That is, the lower stacking tray 137 may be moved so that the sheets stacked on the lower stacking tray 137 and the tray paddle 301 can be brought close to each other.

  In this embodiment, when the lower stacking tray 137 is lowered to the first height, the tray paddle 301 is lowered to bring the sheets stacked on the lower stacking tray 137 closer to each other. However, the present invention is not limited to this. . For example, a configuration in which the tray paddle is continuously lowered in accordance with the upstream surface height of the sheets stacked on the lower stacking tray may be employed. In addition, a plurality of lower tray area detection sensors and a plurality of flag portions may be provided so that the lower tray area detection sensor is lowered more gradually. In other words, the tray paddle 301 may be lowered as the amount of sheets stacked on the lower stacking tray 137 increases.

  In this embodiment, the stacking position of the sheets is detected based on the position in the height direction of the stacking tray using the stacking tray position detecting unit. However, the present invention is not limited to this. For example, a sheet count unit that counts the number of sheets discharged from the bundle discharge roller pair 130 may be provided, and the above-described control may be performed based on the number of sheets counted by the sheet count unit. Further, the amount of lowering of the tray may be detected by the on / off of the encoder 520 and the lower tray position detection sensor S13, and control may be performed to lower the transfer position of the tray paddle 301 in small increments. In other words, the tray paddle 301 may be lowered as the amount of sheets stacked on the lower stacking tray 137 increases.

  In the present embodiment, the description has been given using the sheets stacked on the lower stacking tray 137, but the present invention is not limited to this. The upper stacking tray 136 may be configured in the same manner as the lower stacking tray, and the same control as described above may be performed on the sheets stacked on the upper stacking tray 136.

  In this embodiment, the finisher control unit 618 is mounted on the finisher 100, and the finisher control unit 618 is controlled by the CPU circuit unit 610 mounted on the copier 600 connected online. Is not limited to this. For example, the finisher control unit 618 may be mounted on the copier 600 integrally with the CPU circuit unit 610 and the finisher 100 may be controlled from the copier 600 side.

  Further, in the present embodiment, the description has been made mainly on a sheet (hereinafter referred to as a half size) that is short in the discharge direction such as A4 or LTR size, but it can also be performed on a long sheet (large size) such as A3 or LDR. it can. When the large size is used, the return force is preferably larger than the half size by the larger size. Therefore, it is desirable to lower the half-size position even at the same first transfer position. For example, it is desirable that the half-size first transfer position, the large-size first transfer position, the half-size second transfer position, and the large-size second transfer position are lowered and returned strongly in this order.

1 Composite device (image forming device)
100 finisher (sheet stacker)
130 Bundle discharge roller pair (sheet discharge unit)
137 Lower stacking tray (sheet stacking means)
510 Sheet height detection sensor (sheet stacking means)
170 Abutting member (sheet stacking means)
301 Tray paddle (transfer means)
302 Paddle holder (transfer means)
515a Flag section (stacking tray position detecting means)
520 Encoder (stack tray position detection means)
604 Image forming unit 618 Finisher control unit (control unit)
S13 Lower tray position detection sensor (stacking tray position detection means)
S15 Lower tray area detection sensor (stack tray position detection means)
S16 Lower tray area detection sensor (stack tray position detection means)
S17 Lower tray area detection sensor (stack tray position detection means)

  The present invention relates to a sheet stacking apparatus and an image forming apparatus, and more particularly to a sheet stacking apparatus capable of aligning sheets stacked on a stacking tray and an image forming apparatus including the same.

  Conventionally, sheets discharged to a stacking tray on which sheets are stacked can be aligned in the sheet discharge direction (hereinafter simply referred to as “discharge direction”) and the sheet width direction orthogonal to the discharge direction (hereinafter simply referred to as “width direction”). A sheet stacking apparatus is known (see Patent Document 1).

For example, in the sheet stacking device described in Patent Document 1, when a sheet is discharged to a stacking tray having a stacking surface inclined by the sheet discharge unit, the sheet is transferred upstream by the transfer unit , and the upstream end of the sheet is moved. The sheet is aligned in the discharge direction by abutting against the abutting member. Further, the sheet is aligned in the width direction by moving the pair of alignment members in the width direction and causing the pair of alignment members to abut against both ends of the sheet in the width direction. This is performed every time the sheets are discharged, and the sheets are stacked while lowering the stacking tray so that the stacking height ( upper surface position ) of the sheets stacked on the stacking tray does not exceed a predetermined height.

JP 2002-211829 A

Incidentally, the above sheet stacking apparatus, since the angle between the abutment surface 1170 of the loading surface and the abutment member of the stacking tray 1137 alpha is an acute angle, when impinging on the surface 1170 the upstream end of the sheet abutting, upstream end downward May be curved by receiving a force, resulting in a convex shape indicated by a dotted line Sb in FIG. When the sheets discharged from the discharge roller pair 1130 are stacked while taking such a shape, an air layer is formed between the sheets on the abutting member side, as shown in FIG. Furthermore, the paper surface height Ha on the abutting member side with respect to the paper surface height Hb at the center in the discharge direction becomes relatively high. Therefore, the inclination of the sheet downstream from the central portion in the discharge direction becomes closer to the horizontal as the number of stacked sheets increases.

On the other hand, the transfer unit 1301 of the above-described sheet stacking device appears and disappears from the abutting member side to a predetermined transfer position on the stacking surface of the stacking tray 1137 so as to transfer the sheet on the stacking tray to the abutting member side. It is configured. Further, the sheet surface height of the sheet is controlled to be lowered based on the height Ha on the abutting member side so as not to affect the sheet discharge from the sheet discharge unit. Therefore, if the height Ha of the abutting member relative to the height Hb of the central portion in the discharge direction is relatively increased due to the increase in the loading amount, the sheet surface height of the sheet at the transfer position by the transfer unit is reduced, There is a possibility that the contact pressure between the transfer unit and the sheet may be reduced. As a result, the transfer unit cannot transfer the sheets, and there is a risk of causing a stacking error.

  Further, the discharged sheet has a reaction force when the downstream end is landed on the inclined stacking surface of the stacking tray 1137, and a sliding resistance force between the top surface of the sheets stacked on the stacking tray 1137 after landing, In response, these forces act as braking forces and stop after a predetermined distance. However, when the sheet stacking amount increases, the inclination of the upper surface of the sheets stacked on the stacking tray 1137, which is the landing point at the downstream end of the discharged sheets, becomes nearly horizontal, so the reaction force and sliding at the time of landing The resistance is reduced and the running distance (flying distance) is increased. When the sheet stacking amount increases in this way, the sheet is stacked farther and on the upper surface of the stacking sheet having a small inclination, so that the return along the inclined surface due to the weight of the sheet becomes insufficient, and a stacking deviation may occur. was there.

  SUMMARY An advantage of some aspects of the invention is that it provides a sheet stacking apparatus capable of preventing the occurrence of misalignment of a plurality of sheets stacked on a stacking tray, and an image forming apparatus including the sheet stacking apparatus.

The present invention relates to a sheet stacking apparatus, a sheet discharge unit for discharging sheets, a stacking tray for stacking sheets discharged from the sheet discharge unit, and sheets stacked on the stacking tray below the sheet discharge unit. An abutting member formed to be able to abut the end portion, and a sheet stacking height detection sensor that detects an upper surface position of the sheet stacking height direction of the butting member side of the sheets stacked on the stacking tray. In accordance with the detection result of the sheet stacking height detection sensor, a sheet stacking unit for stacking sheets while lowering the stacking tray, and a sheet stacking height direction provided above the stacking tray are provided. the sheet and the sheet discharged from the discharge portion in contact from above the transport unit which makes abutting and transported toward the abutting member, Sea stacked on the stacking tray Performed in a stacking amount detector for detecting the stacking amount, the stacking amount of sheets is detected by the stacking amount detecting unit is increased, the control of lowering the sheet stacking position in the height direction of the transfer portion at the time of transfer And a control unit.

According to the present invention, when the amount of sheets stacked on the stacking tray is increased, the relative distance between the uppermost sheet on the stacking tray and the transfer unit is reduced, thereby stacking a plurality of sheets stacked on the stacking tray. The occurrence of deviation can be prevented.

It is sectional drawing which shows typically the whole structure of the composite apparatus which concerns on embodiment of this invention. It is sectional drawing which shows the finisher which concerns on this embodiment typically. It is a block diagram of the control part which controls the compound apparatus concerning this embodiment. It is a block diagram of the finisher control part which controls the finisher concerning this embodiment. It is a perspective view which shows the width direction alignment part provided in the finisher which concerns on this embodiment. It is a perspective view which shows the discharge direction alignment part provided in the finisher which concerns on this embodiment. It is a figure which shows the stand-by position and transfer position of the tray paddle of the discharge direction alignment part which concern on this embodiment. It is a perspective view which shows the lower stacking tray provided in the finisher which concerns on this embodiment. FIG. 6 is a perspective view illustrating a lower tray area detection sensor that detects a position in a sheet stacking height direction of a lower stacking tray according to the present embodiment. It is a diagram illustrating a sheet stacking height detection sensor for detecting a sheet stacking height of the sheets stacked on the lower stack tray according to the present embodiment. It is a figure which shows the state which a front alignment member, a back alignment member, a paddle holder, and a lower stacking tray are located in a home position. It is a figure which shows the state which moved the front alignment member, the back alignment member, and the paddle holder to the sheet | seat reception position. It is a figure which shows the state in which a tray paddle aligns a sheet | seat in a discharge direction in the 1st transfer position. It is a figure which shows the state which a front alignment member and a back alignment member align a sheet | seat in the width direction. FIG. 6 is a diagram illustrating a state where sheets are aligned in the width direction by further lowering the front alignment member and the back alignment member in accordance with the position of the lower stack tray in the sheet stacking height direction . It is a figure which shows the state which the sheet | seat loaded on the lower stacking tray increased, and the lower stacking tray fell to the 2nd height. It is a figure showing the state where a tray paddle descends from the 1st transfer position to the 2nd transfer position. 6 is a flowchart showing a sheet stacking operation on a lower stacking tray by a finisher according to the present embodiment. It is sectional drawing which shows typically the stacking tray of the sheet | seat stacking apparatus which concerns on a prior art example.

  Hereinafter, an image forming apparatus including a sheet stacking apparatus according to an embodiment of the present invention will be described with reference to the drawings. The image forming apparatus according to the present embodiment is an image forming apparatus provided with a sheet stacking apparatus capable of aligning sheets stacked on a stacking tray, such as a copying machine, a printer, a facsimile, and a composite device thereof. The following embodiments will be described using a monochrome / color composite device (hereinafter referred to as “composite device”) 1 as an image forming apparatus.

  Hereinafter, a composite device 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 18. First, the overall configuration of the composite device 1 will be described along the movement of the seat with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view schematically showing the overall structure of a composite device 1 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing the finisher 100 according to the present embodiment.

  As shown in FIG. 1, the composite apparatus 1 according to the present embodiment includes a copying machine 600 that forms an image on a sheet, and a finisher 100 as a sheet stacking apparatus. The finisher 100 according to the present embodiment is configured to be detachable from the copying machine 600 and can be used as an option for the copying machine 600 that can be used alone.

  In the present embodiment, the detachable finisher 100 described above will be used. However, in the present invention, the finisher 100 and the copying machine 600 may be an integrated composite device. In the following, the position where the user faces the operation unit 601 for performing various inputs / settings on the composite device 1 is referred to as “front” of the composite device 1, and the back side of the composite device is referred to as “back”. That is, FIG. 1 shows the internal configuration of the composite device 1 as seen from the front side, and the finisher 100 is connected to the side of the copier 600.

  The copying machine 600 includes an operation unit 601, a document feeding device 602 that can feed a document, an image reader 603 that reads information on a document fed from the document feeding device 602, and an image that forms an image on a sheet. Forming portion 604. Further, the copier 600 includes a sheet storage unit 605 that stores sheets, and a sheet feeding unit 606 that feeds sheets stored in the sheet storage unit 605 to the image forming unit 604.

  When a document is set on the document feeder 602 of the copying machine 600, the document is fed one by one from the first page in order, and the image information of the document is read by the image reader 603. When the image information is read, toner images of colors of yellow, magenta, cyan, and black are formed on the photosensitive drums 914a to 914d of the image forming unit 604 based on the read image information. In parallel with the toner image forming operation, the sheet feeding unit 606 selectively feeds the sheets from the feeding cassettes 909 a and 909 b of the sheet storage unit 605. Then, at a predetermined timing, the sheet is sent to the transfer positions of the photosensitive drums 914a to 914d, and the toner images of the respective colors formed on the photosensitive drums 914a to 914d are sequentially superimposed and transferred onto the sheet. Thereafter, the unfixed toner image formed on the sheet is fixed by the fixing device 904, and the sheet is sent to the finisher 100 by the discharge roller pair 907.

  In the case of duplex printing, after the sheet is reversed by the reversing roller 905, the reversed sheet is conveyed by the conveying rollers 906a to 906f provided in the reversing conveyance path to the image forming unit 604, and the above is repeated.

  The finisher 100 is connected to the downstream side of the copier 600, and can introduce a sheet sent from the copier 600 and perform saddle processing online. As shown in FIG. 2, the finisher 100 includes a finisher main body 400 and an inserter 900 that can insert a sheet into a conveyance path 109 inside the finisher main body 400. The inserter 900 is provided in the upper part of the finisher main body 400. For example, the inserter 900 is used to insert an insert sheet between the first page, the last page of a sheet bundle, or a sheet on which an image is formed by the copying machine 600. is there.

  The sheet fed from the copying machine 600 is first delivered to the entrance roller pair 102 of the finisher 100. At this time, the sheet delivery timing is simultaneously detected by the entrance sensor 101. While the sheet delivered to the entrance roller pair 102 passes through the conveyance path, the lateral registration detection sensor 104 detects a lateral registration error in the sheet width direction (hereinafter simply referred to as “width direction”) with respect to the center position. When the horizontal registration detection sensor 104 detects a horizontal registration error, the shift unit 108 performs a horizontal registration detection process.

When the lateral registration detection process by the shift unit 108 is completed, the sheet is conveyed by the conveyance roller pair 110 and further conveyed downstream by the buffer roller pair 115. Here, when the sheet is discharged onto the upper stacking tray 136, the upper path switching member 118 by a driving unit such as a solenoid (not shown) is moved to the position of the broken line shown in FIG. 2, the sheet on the path conveying path 117 Then, the sheet is discharged to the upper stacking tray 136 by the upper discharge roller pair 120. On the other hand, when the sheet is discharged to the lower stacking tray 137, the upper path switching member 118 is moved to the position of the solid line shown in FIG.

Here, when the sheet conveyed to the bundle conveying path 121 is subjected to saddle stitching (saddle processing), the saddle path switching member 125 is moved to the position of the broken line shown in FIG. 2 by a drive unit such as a solenoid (not shown). As a result, the sheet is guided to the saddle path 133 and is conveyed to the saddle unit 135 by the saddle entrance roller pair 134 to perform saddle stitching processing. The description of the saddle stitching process is omitted here. On the other hand, when the saddle stitching process is not performed, the saddle path switching member 125 is moved to the position of the solid line shown in FIG. 2, and the sheets are sequentially conveyed onto the processing tray 138 of the staple unit 127. The sheets conveyed onto the processing tray 138 are aligned in the sheet discharge direction (hereinafter simply referred to as “discharge direction”) and the width direction, and then are bound by the stapler 132. The sheet processing in the stapling unit 127 will not be described here.

The sheets that have undergone predetermined sheet processing by the staple unit 127 are discharged to a lower stacking tray 137 as a stacking tray by a bundle discharge roller pair 130 serving as a sheet discharging unit. When the predetermined sheet processing is not performed in the staple unit 127, the sheet is transferred from the lower discharge roller pair 128 to the bundle discharge roller pair 130 and discharged to the lower stacking tray 137. Thereafter, the sheets discharged to the lower stacking tray 137 are aligned in the width direction and the discharge direction on the lower stacking tray 137 by the width direction aligning unit 200 and the discharge direction aligning unit 300. The width direction alignment by the width direction alignment unit 200 and the discharge direction alignment process by the discharge direction alignment unit 300 will be described in detail later. The lower stack tray 137, the sheet stacking height (surface position) is detected by the sheet stack height detection sensor 510 will be described later, as the upper surface of the sheet reaches a predetermined height, the sheet stacking height detection sensor 510 The sheets are stacked while descending according to the detection result. The lower stacking tray 137, the sheet stacking height detection sensor 510, and the butting member 170 constitute a sheet stacking unit , and the lower stacking tray 137 will be described in detail later.

  Next, the control unit 6 that controls the composite device 1 according to the present embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 is a block diagram of the control unit 6 that controls the composite device 1 according to the present embodiment. FIG. 4 is a block diagram of the finisher control unit 618 that controls the finisher 100 according to the present embodiment.

  As shown in FIG. 3, the control unit 6 includes a CPU circuit unit 610, a document feeding device control unit 614, an image reader control unit 615, an image signal control unit 616, a printer control unit 617, and a finisher control unit. 618. In the present embodiment, the CPU circuit unit 610, the document feeder control unit 614, the image reader control unit 615, the image signal control unit 616, and the printer control unit 617 are mounted on the copier 600, and the finisher control unit 618 is It is mounted on the finisher 100.

  The CPU circuit unit 610 includes a CPU 611, a ROM 612, and a RAM 613. In accordance with the program stored in the ROM 612 and the instruction information input from the operation unit 601, the CPU 611 controls the document feeder control unit 614, the image reader control unit 615, the image signal control unit 616, the printer control unit 617, and the finisher control unit. 618 etc. are controlled. The RAM 613 is used as an area for temporarily storing control data and a work area for operations associated with control.

  The document feeder control unit 614 controls the document feeder 602, and the image reader controller 615 controls the image reader 603 that reads information on the document fed from the document feeder 602 (see FIG. 1). ). Note that the document data read by the image reader controller 615 is output to the image signal controller 616. A printer control unit 617 controls the copying machine 600. The external interface 619 is an interface for connecting the external computer 620 and the copying machine 600. For example, the print data input from the computer 620 is developed into an image and output to the image signal control unit 616. The image data output to the image signal control unit 616 is output to the printer control unit 617, and an image is formed by the image forming unit 604.

  As shown in FIG. 4, the finisher control unit 618 includes a CPU (microcomputer) 701, a RAM 702, a ROM 703, input / output units (I / O) 705a to 705e, a communication interface 706, and a network interface 704. I have. The finisher control unit 618 includes a transport control unit 707, an intermediate processing tray control unit 708, a binding control unit 709, a stacking tray alignment control unit 710, and a stacking tray control unit 711. The finisher control unit 618 controls various drive motors and sensors shown in FIG. 4 by exchanging information with the CPU circuit unit 610 to perform overall drive control of the finisher 100. For example, the finisher control unit 618 causes the stacking tray alignment control unit 710 capable of executing proximity control described later to execute proximity control.

  Next, the width direction alignment unit 200 that performs alignment processing in the width direction of the sheets discharged to the lower stacking tray 137 will be described with reference to FIG. 5 in addition to FIG. FIG. 5 is a perspective view showing the width direction aligning portion 200 provided in the finisher 100 according to the present embodiment. In the following, the width direction is referred to as the front and back direction.

  As shown in FIG. 2, the width direction alignment unit 200 is provided above the lower stacking tray 137. Further, as shown in FIG. 5, the width direction alignment unit 200 includes a front alignment unit 201b disposed on the front side, a rear alignment unit 201a disposed on the rear side, an upper stay 202, and an alignment member lifting motor M11. And an alignment member elevating HP sensor S11. The front alignment unit 201b and the back alignment unit 201a are attached to the upper stay 202 so as to be symmetrical in the front-rear direction, and the upper stay 202 is supported by the finisher body 400.

  The front alignment unit 201b includes an arm-shaped front alignment member 203b, a pulley support plate 204b, a front alignment member slide motor M9, and a front alignment member HP sensor S9. The back alignment unit 201a includes an arm-shaped back alignment member 203a, a pulley support plate 204a, a back alignment member slide motor M10, and a back alignment member HP sensor S10. Since the front alignment unit 201b and the back alignment unit 201a have the same basic configuration, the configuration of the back alignment unit 201a will be described here, and the front alignment unit 201b is denoted by the same reference numeral. Description is omitted.

  The rear end of the rear alignment member 203a is supported by the slide member 206, and the slide member 206 is supported by the first alignment support shaft 205 so as to be rotatable and slidable. Further, the slide member 206 holds the second slide drive transmission belt 209 with the slide position detection member 208, and the second slide drive transmission belt 209 is stretched over a pair of slide drive transmission pulleys 210a and 210b. Yes. The slide drive transmission pulleys 210a and 210b are supported by a pulley support shaft 211 that is caulked and coupled to a pulley support plate 204a. The slide drive transmission pulley 210a is connected to a rear alignment member slide motor via a first slide drive transmission belt 212. It is connected to M10.

  The back alignment member 203a is moved in the front-rear direction by the slide member 206 being slid along the first alignment support shaft 205 by the drive of the back alignment member slide motor M10, and the leading end is moved to the end in the sheet width direction. The sheets are brought into contact with each other to align the sheets in the width direction. At this time, the home position in the front and back direction of the back alignment member 203a is detected by the back alignment member HP sensor S10 attached to the upper stay 202 via the alignment position detection support plate 214. Then, based on the detected home position and the like, movement control in the front-rear direction is performed by the stacking tray alignment control unit 710 of the finisher control unit 618. The home position in the near back direction of the back aligning member 203a is a position in the near back direction where the sheet can be discharged onto the lower stacking tray 137.

  The first alignment support shaft 205 is supported by alignment member elevating pulleys 215a and 215b, and the alignment member elevating pulley 215a is connected to the second elevating pulley 217 via a drive transmission belt 216. The second elevating pulley 217 is attached to the elevating transmission shaft 218 with a D-cut, and the third elevating pulley 219 is connected to the elevating transmission shaft 218. The third lifting pulley 219 is connected to the alignment member lifting motor M11 via the drive transmission belt 220.

The back aligning member 203a moves up and down as the first aligning support shaft 205 rotates via the elevating transmission shaft 218 by driving the alignment member elevating motor M11. At this time, the rotation amount of the back alignment member 203a is restricted by the second alignment support shaft 207. Further, the flag portion 215f provided on the alignment member elevating pulley 215b turns on and off the alignment member elevating HP sensor S11 that detects the home position in the elevating direction of the inner alignment member 203a, thereby raising and lowering the inner alignment member 203a. The home position in the direction is detected. Then, based on the detected home position in the raising / lowering direction and the like, movement control of the raising / lowering position is performed by the stacking tray alignment control unit 710 of the finisher control unit 618. Since the back alignment member 203a and the front alignment member 203b are connected via the lifting transmission shaft 218, the front alignment member 203b is used to control the lift position of the back alignment member 203a by the stacking tray alignment control unit 710. Synchronize. The home position at the lift position is a position in the lift direction at which the sheet can be discharged onto the lower stacking tray 137.

  Next, a discharge direction alignment unit 300 that performs alignment processing in the discharge direction of the sheets discharged to the lower stacking tray 137 will be described with reference to FIGS. 6 and 7 in addition to FIG. FIG. 6 is a perspective view showing the discharge direction alignment unit 300 provided in the finisher 100 according to the present embodiment. FIG. 7 is a diagram illustrating the standby position and the transfer position of the tray paddle 301 of the discharge direction alignment unit 300 according to the present embodiment.

  As shown in FIG. 2, the discharge direction alignment unit 300 is provided above the lower stacking tray 137. Specifically, the discharge direction alignment unit 300 is supported by a substantially central portion of an upper opening / closing guide 149 provided so as to be positioned above the bundle discharge roller pair 130. The discharge direction aligning unit 300 lowers a tray paddle 301 (to be described later) while rotating it from above the bundle discharge roller pair 130, thereby dropping a sheet discharged from the bundle discharge roller pair 130 onto the lower stacking tray 137. It is made to abut against 170. The abutting member 170 is provided below the bundle discharge roller pair 130 on the upstream side in the sheet discharge direction (hereinafter simply referred to as “upstream side”) in which the sheets are discharged to the lower stacking tray 137 (see FIG. 11). ).

As shown in FIG. 6, the discharge direction alignment unit 300 includes a tray paddle 301 and a paddle holder 302, and the tray paddle 301 and the paddle holder 302 serve as a transfer unit that causes the sheet to abut against the abutting member 170. It is composed.

  The tray paddle 301 has a plurality of paddles and is rotatably supported at the tip of the paddle holder 302. The rotation shaft 315 of the tray paddle 301 is connected to a tray return pulley 316a, and the tray return pulley 316a is connected to the tray return pulley 316b via a drive transmission belt. The tray return pulley 316b is connected to a holder support shaft 303 rotatably supported by the upper opening / closing guide 149. The holder support shaft 303 is drivingly connected to the bundle discharge roller pair 130 via a gear train 317. . That is, the tray paddle 301 is configured to rotate in synchronization with the bundle discharge roller pair 130 that is rotated by driving the bundle discharge motor M5.

The base end portion of the paddle holder 302 is supported by the holder support shaft 303 and is engaged with a paddle lifting pulley 305 supported by the holder support shaft 303. A lift link pulley 306 is connected to the paddle lift pulley 305, and the lift link pulley 306 is connected to the lift link pulley 309 via a drive transmission belt 307. The lifting link pulley 309 is connected to the lifting gear 312 via the drive transmission belt 310, and the lifting gear 312 is connected to the tray paddle lifting motor M12. As a result, the driving force of the tray paddle lifting motor M12 is transmitted to the paddle holder 302, and the paddle holder 302 rotates (lifts), so that the tray paddle 301 supported at the tip of the paddle holder 302 can freely move up and down. The tray paddle elevating motor M12 is attached to the elevating motor support plate 313, and the elevating motor support plate 313 is attached to the upper stay 202 (see FIGS. 5A and 5B). The paddle elevating pulley 305, elevating link pulley 306, drive transmission belt 307, elevating link pulley 309, drive transmission belt 310, elevating gear 312 and tray paddle elevating motor M12 constitute a drive unit for elevating the tray paddle 301. To do.

Home position of Padoruhoruda 302, a tray paddle HP sensor S12 which is attached to the upper opening and closing guide 149 is flag portion 302f of Padoruhoruda 302 Ru is detected by blocking. Based on the detected home position and the like, the stacking tray alignment control unit 710 performs movement control of the rotation position. For example, the paddle holder 302 is shown in FIG. 7A where the sheet is received above the bundle discharge roller pair 130 and in FIG. 7B where the sheet on the lower stacking tray 137 abuts against the abutting member 170. Movement control is performed between the first transfer position and the first transfer position. Further, the paddle holder 302 is further moved downward from the first transfer position and controlled to move to the second transfer position shown in FIG. 7C in which the relative distance from the uppermost sheet stacked on the lower stacking tray 137 is reduced. Is done. Further, the paddle holder 302 moves to the home position accommodated in the upper opening / closing guide 149 after the end of the job (see, for example, FIG. 6B). Thus, the paddle holder 302 (tray paddle 301) according to this embodiment is controlled to move to the home position, the receiving position, the first transfer position, and the second transfer position. Note that these movement controls will be described in detail later.

Next, an elevating mechanism of the lower stacking tray 137 for stacking discharged sheets and movement control in the sheet stacking height direction will be described with reference to FIGS. First, the raising / lowering mechanism of the lower stacking tray 137 will be described with reference to FIGS. FIG. 8 is a perspective view showing the lower stacking tray 137 provided in the finisher 100 according to the present embodiment. FIG. 9 is a perspective view showing lower tray area detection sensors S15 to S17 that detect the position in the sheet stacking height direction of the lower stacking tray 137 according to the present embodiment.

As shown in FIGS. 8A and 8B, the lower stacking tray 137 includes an elevating unit 500, and a pair of pinion gears 501a and 501b built in the elevating unit 500 is a pair of racks 509a and 509b. Move up and down. Specifically, as shown in FIG. 8C, the pinion gear 501a is connected to the first elevating gear 502 via the second elevating gear 503 and the third elevating gear 504, and the first elevating gear 502 is provided. Is connected to the lifting pulley 505. The lifting pulley 505 is connected to the lower tray lifting motor M13 via the lifting belt 506. The pinion gear 501b is connected to the third elevating gear 504 via the elevating shaft 507. As described above, the lower stacking tray 137 is driven by the lower tray lifting motor M13 so that the pinion gear 501a and the pinion gear 501b rotate in synchronization with each other, and moves up and down by moving on the racks 509a and 509b. It has become.

An encoder 520 is attached to the first elevating gear 502, and the lower tray position detection sensor S13 detects the on / off state of the encoder 520, thereby detecting the rotation amount of the lower tray elevating motor M13. . Then, the lowering amount of the lower stacking tray 137 is detected from the rotation amount of the lower tray lifting motor M13, and it is possible to detect how much the lower stacking tray 137 is lowered from the initial position. The initial position is a position where the lower stacking tray 137 is positioned when the job is started, and is hereinafter referred to as a home position. Further, the encoder 520 and the lower tray position detection sensor S13 constitute a stacking tray position detection unit , and can also form a stacking amount detection unit .

Further, as shown in FIG. 9A, the lower side of the lower stacking tray 137 (the lifting unit 500 side) is a lower side as a stacking tray position detecting unit that can constitute a stacking amount detecting unit at the upstream end. Tray area detection sensors S15 to S17 are mounted side by side in the discharge direction. The lower tray area detection sensors S15 to S17 are turned on when a plurality of flag portions serving as stacking tray position detection units provided at predetermined positions on the area detection plate 515 shield each of the lower tray area detection sensors S15 to S17. It can be switched off. The lower stacking tray 137 has its position in the sheet stacking height direction detected by switching on and off the lower tray area detection sensors S15 to S17 by a plurality of flag portions provided at predetermined positions of the area detection plate 515. It is like that.

  For example, when the lower stacking tray 137 is located at the home position, the lower tray area detection sensor S15 is turned on by being shielded by the flag portion 515a shown in FIG. 9B, and the lower tray area detection sensors S16 and S17 are shielded from light. It is not (off). That is, when the lower tray area detection sensor S15 is on and the lower tray area detection sensors S16 and S17 are off, it is determined that the lower stacking tray 137 is located at the home position. Thereafter, when the sheet stacking amount increases and descends to the first height, the lower tray area detection sensor S16 is turned on by being shielded by a flag portion (not shown) provided on the area detection plate 515, and the lower tray area detection sensor S17. Is not shielded (off). That is, when the lower tray area detection sensors S15 and S16 are on and the lower tray area detection sensor S17 is off, it is determined that the lower stacking tray 137 is positioned at the first height. Further, when the sheet stacking amount increases and descends to the second height, the lower tray area detection sensor S17 is also shielded by a flag portion (not shown) provided on the area detection plate 515 and turned on. That is, when the lower tray area detection sensors S15, S16, and S17 are on, it is determined that the lower stacking tray 137 is positioned at the second height.

As described above, the finisher 100 according to the present embodiment is provided with two types of sensors that detect the position of the lower stacking tray 137 in the sheet stacking height direction . For example, by detecting with the encoder 520, the amount of movement of the lower stacking tray 137 can be detected in detail. In addition, even when there is a possibility that the actual movement amount and the detection amount may deviate if the elevation is repeated due to backlash or the like of the drive unit, the lower stack tray 137 is detected by the detection by the lower tray area detection sensors S15 to S17. It is possible to detect that the vehicle has been lowered to a predetermined position.

In the present embodiment, the lower tray area detection sensors S15 to S17 are used to detect the first height and the second height of the lower stacking tray 137. However, the present invention is not limited to this. For example, a plurality of lower tray area detection sensors may be used so that a plurality of sheet stacking height positions are detected stepwise.

Next, the control operation in the sheet stacking height direction of the lower stacking tray 137 will be described with reference to FIG. FIG. 10 is a diagram illustrating a sheet stacking height detection sensor 510 that detects the stacking height (upper surface position) of the sheets stacked on the lower stacking tray 137 according to the present embodiment.

Sheet stacking movement control in the height direction of the lower stack tray 137 in the sheet stacking height detection sensor 510 to the upper surface position of the loading surface 137a and the sheet stacking height direction of the sheets stacked on the stacking surface 137a of the lower stack tray 137 This is done by detecting. The sheet stacking height detection sensor 510 is provided below the bundle discharge roller pair 130 and upstream of the lower stacking tray 137 (abutting member side) so as not to affect the sheet discharge. The position of the sheet stacking height direction is detected.

As shown in FIG. 10, the sheet stacking height detection sensor 510 includes a first light receiving sensor 510a, a second light receiving sensor 510b, a third light receiving sensor 510c, and a light emitting sensor 510d. The sheet stacking height detection sensor 510 turns each sensor on and off by blocking the light from the light emitting sensor 510d received by the first to third light receiving sensors 510a to 510c by the stacked sheets and the like. Detect. The lower stacking tray 137 is raised and lowered according to the detection result of the sheet stacking height detection sensor 510.

  For example, at the start of a job in which no sheets are stacked on the lower stacking tray 137 (for example, when positioned at the home position), only the third light receiving sensor 510c is shielded from light by the lower stacking tray 137 and is in an on state. . That is, when only the third light receiving sensor 510c is on, it is determined that there is no sheet in the lower stacking tray 137 or the stacking height is low, and the lower stacking tray 137 is not lowered. Thereafter, the sheets are sequentially stacked, and the second light receiving sensor 510b is shielded from light by the stacked sheets. When the second light receiving sensor 510b is turned on, the lower tray lifting motor M13 is driven to drive the second light receiving sensor 510b. Is lowered until is turned off (light receiving state). In this way, each time the second light receiving sensor 510b is turned on, the lower tray elevating motor M13 is driven, and the lower stacking tray 137 is repeatedly lowered to stack the sheets while lowering the lower stacking tray 137. Go. The lower stacking tray 137 is provided with a lower tray sheet presence / absence detection sensor S21 and a sheet presence / absence detection flag 516, and the presence / absence of a sheet is detected by turning on / off the lower tray sheet presence / absence detection sensor S21.

Next, the sheet stacking operation on the lower stacking tray by the finisher 100 according to the present embodiment will be described with reference to FIGS. 11 to 17 along the flowchart shown in FIG. FIG. 11 is a diagram illustrating a state in which the front alignment member 203b, the back alignment member 203a, the paddle holder 302, and the lower stacking tray 137 are located at the home position. FIG. 12 is a diagram illustrating a state in which the front alignment member 203b, the back alignment member 203a, and the paddle holder 302 are moved to the sheet receiving position. FIG. 13 is a diagram illustrating a state in which the tray paddle 301 aligns sheets in the discharge direction at the first transfer position. FIG. 14 is a diagram illustrating a state in which the front alignment member 203b and the back alignment member 203a align the sheets in the width direction. FIG. 15 is a diagram illustrating a state in which the front alignment member 203b and the back alignment member 203a are further lowered according to the stacking height (upper surface position) of the lower stacking tray 137 to align the sheets in the width direction. FIG. 16 is a diagram illustrating a state where the number of sheets stacked on the lower stacking tray 137 is increased and the lower stacking tray 137 is lowered to the second height. FIG. 17 is a diagram illustrating a state in which the tray paddle 301 is lowered from the first transfer position to the second transfer position. FIG. 18 is a flowchart showing a sheet stacking operation on the lower stacking tray 137 by the finisher 100 according to this embodiment.

  When the user sets the unbound bottom discharge stacking mode and starts the unbound bottom stacking mode, the front alignment member 203b and the back alignment member 203a are initially operated to move to the home position (step S801). Similarly, the paddle holder 302 is initially moved to the home position, and the lower stacking tray 137 is initially moved to the home position (steps S802 and S803). When the front alignment member 203b, the back alignment member 203a, the paddle holder 302, and the lower stacking tray 137 are initially operated and moved to the home position or the initial position, the state shown in FIG. 11 is obtained.

  Next, after the initial operation is completed, the front alignment member 203b, the back alignment member 203a, and the tray paddle 301 are moved to the receiving position shown in FIG. First, according to the sheet size information input by the operation unit 601, the front alignment member 203b and the back alignment member 203a are slid by a predetermined amount in the front-rear direction and then rotated by a predetermined amount. Similarly, the paddle holder 302 is rotated by a predetermined amount. The receiving position is a position where the distance between the front alignment member 203b and the back alignment member 203a is set to be a predetermined amount larger than the length in the width direction of the sheet and does not interfere with the discharged sheet. Further, the tray paddle 301 is not in contact with the sheet being discharged. Since the lower stacking tray 137 has the home position as the receiving position, preparation for receiving sheets is completed.

  Next, a sheet on which an image has been formed by the above-described image forming operation is fed from the discharge roller pair 907 of the copying machine 600 to the finisher 100 and discharged from the bundle discharge roller pair 130 to the lower stacking tray 137 (step S804). When the trailing edge of the sheet passes through the nip of the bundle discharge roller pair 130, the tray paddle 301 is lowered from the sheet receiving position to the first transport position. When the tray paddle 301 is lowered, the tray paddle 301 comes into contact with the sheet discharged from the bundle discharge roller pair 130 and drops the sheet onto the lower stacking tray 137. At this time, since the tray paddle 301 rotates in synchronization with the bundle discharge roller pair 130, the sheet S is abutted against the abutting member 170 while being dropped on the lower stacking tray 137, as shown in FIG. It is aligned with the discharge direction (step S805). The timing for rotating the paddle holder 302 starts after a predetermined time after the trailing edge of the sheet S passes through the nip, and the tray paddle 301 is moved at the first transfer position (the position shown in FIG. 13) for a predetermined time. After rotating, it rises to the receiving position (position shown in FIG. 12).

  Next, as shown in FIG. 14, the front alignment member 203b and the back alignment member 203a waiting at a position larger than the length in the width direction of the sheet S by a predetermined amount (A shown in FIG. 14B) are set to the sheet width. And the sheet S is sandwiched and aligned in the width direction. When the sheet S is nipped and aligned in the width direction, the state shown in FIG. 14C is obtained, and the sheet S is aligned in the width direction at a predetermined position on the lower stacking tray 137 (step S806). When the alignment in the width direction of the sheet S is completed, the front alignment member 203b and the back alignment member 203a are moved to the receiving position shown in FIG.

  Next, the state of the second light receiving sensor 510b is confirmed. If the second light receiving sensor 510b is on, the lower stacking tray 137 is lowered until the second light receiving sensor 510b is turned off (steps S807 and S808). On the other hand, if the second light receiving sensor 510b is off, the next sheet is received and this is performed every time the sheet is discharged. In this manner, discharge of sheets, alignment in the discharge direction, alignment in the width direction, and lowering of the lower stacking tray 137 are repeated, and the sheets are sequentially stacked on the lower stacking tray 137.

  By continuing the above-described control, when the lower stacking tray 137 moves to a position that is lowered by a certain amount from the home position, the lower tray position detection sensor S13 detects that the lower loading tray 137 has been lowered by a certain amount (step S809). . Then, the alignment member elevating motor M11 is driven, and the front alignment member 203b and the back alignment member 203a are lowered from the position shown in FIG. 15A to the position shown in FIG. 15B, and the sheets can be aligned in the width direction. It moves to the correct position (step S810). The front alignment member 203b and the back alignment member 203a are configured to be lowered to a position where the sheets can be aligned in the width direction as the amount of sheets stacked on the lower stack tray 137 exceeds a predetermined amount. Yes. Thereby, for example, even when the downstream side of the sheet is in a lying state (see FIG. 16), the front alignment member 203b and the back alignment member 203a can be aligned in the width direction. Here, the state in which the sheets fall asleep means a state in which the inclination of the uppermost sheet stacked on the lower stacking tray 137 approaches the horizontal and becomes smaller.

  When the amount of sheets S stacked on the lower stacking tray 137 increases and the lower stacking tray 137 descends to the first height, the lower tray area detection sensor S16 is turned on (step S811). When the lower tray area detection sensor S16 is turned on, the rotation amount of the paddle holder 302 is set to the second transfer position where the relative distance between the tray paddle 301 and the sheets stacked on the lower stacking tray 137 is reduced (step S812). That is, the tray paddle 301 is set to transfer the sheet at the second transfer position after the sheet stacking amount exceeds a predetermined stacking amount. Note that switching between the first transfer position and the second transfer position is performed while the sheet is being discharged, and image formation or the like is not waited during that time. If the sheet is not the final sheet, the process proceeds to step S804 and the above is repeated. If the sheet is the final sheet, the job is terminated (step S813).

As described above, the finisher 100 according to the present embodiment moves the tray paddle 301 to the second position below the first transfer position when the stack amount of sheets stacked on the lower stack tray 137 exceeds a predetermined stack amount. The sheet is transferred toward the abutting member 170 at the transfer position. For this reason, when the sheet stacking amount increases, the inclination of the sheet upper surface (uppermost sheet) becomes smaller, and even when the upper surface position of the sheet at the first transfer position becomes lower, the tray paddle 301 and the sheet are not aligned . It can prevent that a contact pressure becomes small. Accordingly, it is possible to prevent occurrence of sheet stacking deviation that occurs because the sheets cannot be transferred. Further, since the transfer is performed at the second transfer position located below the first transfer position, the transfer force can be increased.

  Further, in the finisher 100 according to the present embodiment, when the trailing edge of the sheet passes through the nip of the bundle discharge roller pair 130, the paddle holder 302 is rotated to lower the tray paddle 301. For this reason, an increase in the amount of stacked sheets reduces the inclination of the upper surface of the sheet, and the tray paddle 301 transports while dropping the sheet even when the amount of jump when the sheet is discharged from the bundle discharge roller pair 130 can increase. It is possible to prevent the sheet from being unable to move.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above. In addition, the effects described in the embodiments of the present invention only list the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments of the present invention.

  For example, in the present embodiment, when the stacking amount of sheets exceeds a predetermined stacking amount, the paddle holder 302 is moved down so as to be close to the sheets stacked on the tray paddle 301 and the lower stacking tray 137. However, the present invention is not limited to this. For example, it may be a control that adjusts the lowering amount of the lower stacking tray 137 or raises the lower stacking tray by a predetermined amount based on the relative distance between the tray paddle 301 and the sheets stacked on the lower stacking tray 137. That is, the lower stacking tray 137 may be moved so that the sheets stacked on the lower stacking tray 137 and the tray paddle 301 can be brought close to each other.

  In this embodiment, when the lower stacking tray 137 is lowered to the first height, the tray paddle 301 is lowered to bring the sheets stacked on the lower stacking tray 137 closer to each other. However, the present invention is not limited to this. . For example, a configuration in which the tray paddle is continuously lowered in accordance with the upstream surface height of the sheets stacked on the lower stacking tray may be employed. In addition, a plurality of lower tray area detection sensors and a plurality of flag portions may be provided so that the lower tray area detection sensor is lowered more gradually. In other words, the tray paddle 301 may be lowered as the amount of sheets stacked on the lower stacking tray 137 increases.

Further, in this embodiment, detects the load of the sheet based on the sheet stacking height direction position of the stacking tray using a stacking tray position detecting unit is not limited thereto in the present invention. For example, a sheet count unit that counts the number of sheets discharged from the bundle discharge roller pair 130 may be provided, and the above-described control may be performed based on the number of sheets counted by the sheet count unit . Further, the amount of lowering of the tray may be detected by the on / off of the encoder 520 and the lower tray position detection sensor S13, and control may be performed to lower the transfer position of the tray paddle 301 in small increments. In other words, the tray paddle 301 may be lowered as the amount of sheets stacked on the lower stacking tray 137 increases.

  In the present embodiment, the description has been given using the sheets stacked on the lower stacking tray 137, but the present invention is not limited to this. The upper stacking tray 136 may be configured in the same manner as the lower stacking tray, and the same control as described above may be performed on the sheets stacked on the upper stacking tray 136.

  In this embodiment, the finisher control unit 618 is mounted on the finisher 100, and the finisher control unit 618 is controlled by the CPU circuit unit 610 mounted on the copier 600 connected online. Is not limited to this. For example, the finisher control unit 618 may be mounted on the copier 600 integrally with the CPU circuit unit 610 and the finisher 100 may be controlled from the copier 600 side.

  Further, in the present embodiment, the description has been made mainly on a sheet (hereinafter referred to as a half size) that is short in the discharge direction such as A4 or LTR size, but it can also be performed on a long sheet (large size) such as A3 or LDR. it can. When the large size is used, the return force is preferably larger than the half size by the larger size. Therefore, it is desirable to lower the half-size position even at the same first transfer position. For example, it is desirable that the half-size first transfer position, the large-size first transfer position, the half-size second transfer position, and the large-size second transfer position are lowered and returned strongly in this order.

1 Composite device (image forming device)
100 finisher (sheet stacker)
130 Bundle discharge roller pair (sheet discharge unit)
137 Lower stacking tray (sheet stacking section )
510 Sheet height detection sensor (sheet stacking unit )
170 Abutting member (sheet stacking section )
301 Tray paddle (transfer section )
302 Paddle holder (transfer section )
515a Flag section (stacking tray position detection section )
520 encoder (tray position detection unit)
604 Image forming unit 618 Finisher control unit (control unit)
S13 Lower tray position detection sensor (stack tray position detection unit )
S15 Lower tray area detection sensor (stack tray position detection unit )
S16 Lower tray area detection sensor (stack tray position detection unit )
S17 Lower tray area detection sensor (stack tray position detection unit )

Claims (7)

A sheet discharge unit for discharging the sheet;
A stacking tray for stacking sheets discharged from the sheet discharging unit, an abutting member formed to be able to abut an end of the sheet stacked on the stacking tray below the sheet discharging unit, and the stacking tray A sheet height detection sensor for detecting the height of the sheet stacked on the abutting member side, and loading the sheets while lowering the stacking tray according to the detection result of the sheet height detection sensor Sheet stacking means,
Transfer means for contacting the sheet discharged from the sheet discharge unit from above and moving it toward the abutting member;
A load amount detection means for detecting the load amount of the sheets stacked on the stack tray;
A control unit that performs control to bring the transfer unit and the upper surface of the uppermost sheet stacked on the stacking tray closer to each other when the stack amount of sheets detected by the stack amount detection unit increases; ,
A sheet stacking apparatus characterized by that. The transfer means is configured to be movable up and down above the stacking tray,
The loading amount detection means includes a loading tray position detection means for detecting a position in the height direction of the loading tray, and the loading tray position detection means detects the loading tray from the position in the height direction detected by the loading tray position detection means. It is configured to be able to detect the amount of sheets loaded on the stacking tray,
The control unit lowers the transfer means for transfer as the position in the height direction of the stack tray detected by the load tray position detection means is lowered, and the transfer means for transfer and the transfer means Control to reduce the relative distance from the top sheet loaded on the stacking tray.
The sheet stacking apparatus according to claim 1, wherein: The control unit is configured such that the sheet directed toward the abutting member by the transfer unit at the first transfer position until the position in the height direction of the stack tray detected by the stack tray position detection unit is lowered to a predetermined position. When the position of the stacking tray in the height direction is lower than a predetermined position, the transfer means is lowered to a second transfer position below the first transfer position, and is applied to the abutting member. Control to move the sheet toward
The sheet stacking apparatus according to claim 2, wherein: The transfer means is configured to be movable up and down above the stacking tray,
The stacking amount detecting unit includes a sheet counting unit that counts the number of sheets discharged from the sheet discharging unit, and the stacking amount is detected based on the number of sheets discharged from the sheet discharging unit counted by the sheet counting unit. It is configured to be able to detect the amount of sheets loaded on the tray,
The control unit performs control to reduce a relative distance between the transfer unit and the uppermost sheet stacked on the stacking tray when the number of sheets counted by the sheet count unit increases.
The sheet stacking apparatus according to claim 1, wherein: When the number of sheets counted by the sheet counting unit exceeds a predetermined number, the control unit controls to reduce a relative distance between the transfer unit and the uppermost sheet stacked on the stacking tray when the sheet is transferred. I do,
The sheet stacking apparatus according to claim 4, wherein The transfer unit is provided above the sheet discharge unit, and when the sheet is discharged from the sheet discharge unit, the sheet is lowered to cause the sheet to be abutted against the abutting member while being dropped on the stacking tray.
The sheet stacking apparatus according to claim 1, wherein the sheet stacking apparatus is a sheet stacking apparatus. An image forming unit for forming an image on a sheet;
The sheet stacking apparatus according to any one of claims 1 to 6, which aligns a sheet on which an image is formed by the image forming unit.
An image forming apparatus.

Images